In U.S. Pat. No. 4,027,185 (Nodwell et al.) granted May 31, 1977, one of the inventors being common to the present invention, there is described a high intensity radiation source. This reference describes a novel method and apparatus used to produce a high intensity radiation source with an efficient cooling system to increase electrode life. The technique includes the steps of giving a liquid a vortexing motion to form a liquid wall interior of the arc chamber. The liquid cools the arc periphery and limits its diameter.
Improvements have been obtained, however, in increasing electrode life and arc efficiency. It was found in the apparatus described in the aforementioned U.S. Pat. No. 4,027,185 that the radial pressure gradient required within the vortex chamber to smooth out the flow patterns required a liquid pressure higher than desirable. Further, there was an undesirable dump chamber interaction between the vortexing gas and the liquid. This, too, caused liquid droplets to reach the region of the anode tip which was adverse to electrode life.